1. Field of the Invention
This invention relates to a traffic congestion monitoring system.
2. Description of the Related Art
It is conventional to advise police or highway officials of traffic congestion upon main roads by monitoring such congestion visually or by closed-circuit television for example. It is also conventional to advise drivers of congestion locations by broadcasting details of such congestion locations on ordinary or special radio channels to which conventional vehicle radios can be tuned. A drawback of such conventional systems for the drivers is the time delay between the build-up of congestion at a location and the communication of that information to the driver, often with the result that he is unable to avoid that location. The time delay may be worsened by the facts that the broadcasting announcer naturally has to give information about the congestion locations in turn, which also means that the driver has to carry the information in his mind in order to be able to work out a route avoiding all of the congested locations. Moreover, only serious congestion locations may be identified in the announcement, to reduce the interruption of ordinary broadcasting. The transient and aural nature of the presentation of the information to the driver mean that if the driver is not listening to the broadcast or cannot hear the broadcast (for example because the vehicle is in a tunnel or because a passenger is talking to him) when the information is given, he has to await the next bulletin.
Another drawback is that the monitoring involves employing personnel continuously to watch the locations.